Air volume control system and apparatus



NW, 17, 1953 c. HOTCHKISS ET AL 2,659,535

AIR VOLUME CONTROL SYSTEM AND APPARATUS Filed July 28, 1950 2 Sheets-Sheet l INVENTORE? CLIFFEIRD HUTCHKISS B JUSTIN A. DELIEKEL V 1953 c. HOTCHKISS ET AL 2,659,535

AIR VOLUME CONTROL SYSTEM AND APPARATUS Filed July 28, 1950 2 Sheets-Sheet 2 INVENTORS ELQFFDRD HDTEHKISS JUSTIN A DEUEEL ATTORNEYS ?atented v. 1?, 1953 UNITED STATES OFFICE AIR VOLUME CONTROL SYSTEM AND APPARATUS Application July 28, 1950, Serial No. 176,358

8 Claims.

This invention relates generally to actuators and in particular to actuators for air volume control dampers. It concerns a unitary assembly for regulating the flow of conditioned air to a room or other enclosure and utilizes the thermal energy of the conditioned air for moving the damper blades thus making unnecessary any wiring or external electric power.

In controlling the comfort conditions of a room or other enclosure it has in the past been proposed to control the volume of conditioned air admitted into the room. Under such systems of control the temperature of the conditioned air and the velocity of the conditioned air entering the room is maintained constant, the heating requirements for the room being met by variations in the volume of conditioned air admitted to the room, such volume being determined by the position of the conditioned air inlet damper blades. One such apparatus is disclosed in U. S. Reissue Patent 22,870 issued to G. A. Peple, Jr. The present invention comprises an actuator, suitable for use with an air volume damper, which utilizes the thermal energy of the conditioned air. An actuator of this type is disclosed in U. S. Patent No. 1,181,443 issued to W. M. Fulton. The present invention is an improvement in such actuators and provides certain advantages, including accuracy in positioning the conditioned air inlet dampers, as will subsequently be pointed out.

An object of the present invention is to provide a unitary assembly for regulating the flow of conditioned air into a room or other enclosure which utilizes the thermal energy available because of the temperature gradient between the conditioned air and the room air.

A further object is to provide an actuator for an air volume damper which, under certain conditions, positively draws room air over the actuating element, this aspiration of room air being independent of normal room convection currents and of the volume of conditioned air being admitted into the room.

In order that the invention may be more readily understood, reference is had to the accompanying drawings, in which- Fig. l is a front view of the apparatus with the control cover broken away;

Fig. 2 is a right side view of the apparatus taken along the lines II-II of Fig. 1;

Fig. 3 is a left side view of the apparatus taken along the lines III-III of Fig. 1.

Referring now to Fig. l in which is shown a fabricated frame or panel which may be nm at fastened on a wall adjacent an outlet aperture of a conditioned air duct. An extension plate ii of frame it! constitutes a mounting for the actuator or control unit shown. A damper unit, consisting of two curved damper blades, upper blade 12 and lower blade 13, mounted Within the frame 5 0, controls the admission of conditioned air (in dicated by arrows in Figs. 2 and 3) into the room, the temperature of which is to be controlled.

A pivotal linkage i l, shown generally in Fig. 3, provides unitary and synchronous action between the damper blades so that they rotate in unison but in opposite directions. A link it pivotally attached to the lower damper blade i3, is pivotally connected to levers ii and 13. The levers ii and 48 extend along the sides of a casing 22 and are pivotally mounted on a bracket l9, fastened to the frame IE by means of a pivot pin 28. Casing 22 is secured to the plate l I by any suitable means and, as illustrated, is spaced from plate I! by member 35, formed of thermal insulating material, and spacer blocks 36. A cover member 26 is provided to encompass the actuator unit and is detachably secured to the extension plate l i. The casing 22 provides an enclosure or chamber 23 in which is located a thermal responsive member which is the operating element, here shown as a bellows 2!, which contains a volatile fluid causing the bellows 2i to expand upon being heated. The bellows 2! is secured by brackets 25 to the casing 22 and overlies a shaft 25 journaled in the levers l? and i8. Thus, movement of the bellows 2| results in a corresponding movement of the shaft 25 to pivot the levers H and i3 about the stationary pivot 28, journaled in the bracket it. A compression spring 3t, bearing against the extension plate ll, engages a metal plate 32, secured to the lever H by screw 33 and secured to lever ill by screw it. The spring 35 biases the levers ii and it against expansion movement of the bellows 2 i. As has been pointed out, the casing 22 is secured to the plate H but spaced therefrom by a piece of thermal insulating material 35 and metal blocks 33. This mounting for bellows 2 I eilectively insulates it from thermal conduction from the frame it and plate ii.

A room air inlet pipe 33 is secured to one side of the casing 22 and protrudes through the cover 29, thus providing a conduit from the bellows chamber 23 to the room. A tube at! is secured to the opposite side of casing 22 and extends along a line parallel to the damper blades. The tube 40 provides an outlet conduit from the bellows chamber to the room and also serves as an inlet conduit for the duct air. A conduit, here shown as pipe 42, is connected, as shown in Figs. 1 and 3, to the damper housing 44 and projects through an opening in tube 40 to lie concentrically therein. The pipe 42 has an inlet opening 46 exposed to the duct air behind the damper assembly and an outlet opening 48 within the tube 40.

The tube 40 terminates in an opening 50 which is provided with a closure means here shown a a flat valve member 52. The valve member 52 is secured to an L-shaped lever 54 which is pivoted on a pin 56 fastened to the base plate II. A compression type spring 58 is interposed between the lever end 59 and the tube 40 to bias the valve member 52 to closed position. A temperature sensing element, here shown as a bimetal strip 60, is mounted on a pivot pin 62 secured to the base plate II. A block of insulation material 63 is riveted to one end of strip Bi] and abuts the lever end 59. An adjusting screw 64,

threaded through a bracket 66, permits adjustment of the position of member 52 with relation to the outlet 58 thereby providing a control point adjustment. A serrated knob 58 on the end of adjusting screw 64 extends beyond the cover 20 to allow external adjustments to be made. Note that the cover 20 is open at the end adjacent the bimetal 60 and that the bottom of cover 20 has openings 6| therein which permit the circulation of room air over the bimetal 60.

Operation Referring to Figure 1, when the member 52 i in full open position (shown in broken lines in Figure 1), heated air from the duct flows through the pipe 42, out its open end 48 and out of the end 50 in the tube 40. This flow of heated air aspirates room air through the pipe 38 into the casing 22 past the bellows 2|. Under these conditions the bellows 2| will be maintained at room temperature and will be in a relatively contracted position with damper blades I2 and I3 wide open. As the member 52 is moved toward the opening 50, it will reach a position with reference to the opening 50 such that the resistance to the flow of air through the opening 50 will prevent room air from being aspirated through the pipe 38.

When the member 52 moves further toward the open end 56, increasing the resistance to the flow of air therethrough, a portion of the heated air will flow slowly back through the, tube 40 into the casing 22. This slow moving heated air will be cooled somewhat as it moves through the tube 40 but will raise the temperature of bellows 2| above room temperature. A still further closure of open end 50 by the member 52 will cause heated air to flow more rapidly through the tube 40 and into the casing 22. Since the velocity of the flow of this heated air through the tube 40 increases as the member 52 approaches the open end 50, the loss of thermal energy to the wall of tube 40 by the air flow.- ing through the tube 40 will decrease and the temperature of bellows 2| will be increased.

With the apparatus in the position shown in Figures 1, 2, and 3, the bellows 2| is partially expanded and damper blades I2 and I3 are consequently in an intermediate position. The member 52 is positioned by the bimetal strip 69 at a point with reference to the open end such that a portion of the heated air flowing from the pipe 42 flows through the tube 40 establishing the bellows 2| at a temperature somewhat above room temperature. Bellows 2| has assumed an expansive position such that the damper blades I2 and I3 are separated to admit into the room a sufiicient volume of heated air so as to just balance the heat losses from the room.

Should this position of equilibrium be disturbed by increased heat losses from the room, because of decreasing outdoor temperature or for other reasons, the consequent slight upward movement of the free end of strip 86 will move the member 52 slowly away from the opening 50, decreasing the resistance to the flow of heated air out of the open end 50. With such movement less and less heated air will flow into the casing 22 and eventually no heated air will flow thereto and room air will be aspirated into the casing 22. As this takes place, the temperature of bellows 2| will consequently be slowly decreased and will approach room temperature. Consequently damper blades I2 and I3 will be slowly moved in opening direction as bellows 2| contracts. The resulting increased volume of heated air flowing past the damper blades I2 and I3 will eventually again balance the heat losses from the room and the bellows 2| and damper blades I2 and I3 will come to rest at a new position of equilibrium.

Should the heat losses from the room thereafter decrease, because of increasing outdoor temperature or for other reasons, member 52 will be moved toward the open end and heated air will eventuall begin to flow through the tube 40 into the casing 22. As member 52 approaches the open end 58 the velocity and consequently the thermal energy of the heated air passing to casing 22 will increase and the temperature of the bellows 2| will therefore slowly increase. The resulting expansion of bellows 2| will move damper blades I2 and I3 in closing direction. The decreasing volume or heated air flowing past the damper blades I2 and I3 into the room will eventually be such that the heat losses from the room will again be balanced and bellows 2| and damper blades I2 and I3 will assume a new position of equilibrium.

It will be noted that the flow of room air through the pipe 38 into the casing 22 is, under certain conditions, positively induced and aspirated through the casing 22 by the flow of heated air out of the open end 50. The flow of room air past the bellow 2| does not depend on convection currents in the room and is independent of the position of damper blades I2 and I3. As a result there is no loss of control of the temperature of, and consequently the position of, the, bellows 2| as the damper blades I2 and I3 approach their closed position.

It Will be understood that by reversing the direction of movement of the room temperature sensing element 66 and reversing the direction of movement of damper blade-moving linkage, the actuator might be utilized for controlling the admission of cooled, rather than heated air into a room or other enclosure the temperature of which is to be controlled. Additionally bimetal strip might be arranged so that its free end moves upwardly when heated and the linkage between the damper blades I2 and I3 and bellows 2I reversed so that upon an increase in room temperature the member 52 would move away from the open end 50 and the bellows 2| would move in a contracting direction to close damper blades I2 and I3.

From the foregoing description it will be ap parent that many modifications of this invention 5 are possibl h er t e inven ion is. be linio ir y h co e of he pended claims- W hat is claimed is:

i. In an apparatus for; controlling the flow of heated air from a source thereof into a room the temperature of which is to be maintained at a selected value: a thermal sensing element responsive to the temperature of the room, .a th rmal responsive member operable to vary the flow of heated air into the room, an enclosure for aid, thermal responsive member having inlet and outlet openings, a conduit for the transmission of heated air from said source into said enclosure, closure means for said outlet opening operable by said thermal sensing element for selectively directing heated air from said conduit to thermal responsivemember and for utilizthe kinetic energy of the heated air transmitted through said conduit to draw air from the room through. said inlet opening to said thermal responsive member dependant upon the deviation of the room temperature from said selected value.

2. In an apparatus for controlling the flow of heated air from a source thereof into a room the temperature of which is to be maintained at a selected value: a thermal sensing element responsive to the temperature of the room, a thermal responsive member operable to vary the ficw of heated air into the room, an enclosure for said thermal responsive member having inlet and. outlet openings, a conduit extending from said source of heated air into said enclosure and having its outlet directed toward the outlet opening said. enclosure, closure means for the outlet opening in said enclosure operable by said thermal sensing element for selectively directing heated air from said conduit to said thermal responsive member and for utilizing the kinetic energy of the heated air discharged from said conduit outlet to aspirate air from the room through the enclosure inlet opening to said thermal responsive member dependant upon the deviation of the room temperature from said selected value.

3. An apparatus for controlling the flow of heated air from a source thereof into a room the temperature or which is to be maintained at a selected value comprising: a thermal sensing element responsive to the temperature of the room, a thermal responsive member, a damper controlling the flow of heated air into the room, linkage means connecting said thermal responsive member and said damper, said damper being moveable by said member in response to variaticns in the temperature thereof, an enclosure for said thermal responsive member having inlet and outlet openings, a conduit extending from said source of heated air into said enclosure and having its outlet directed toward the outlet opening in the enclosure, closure means for the outlet opening in said enclosure operable by said thermal sensing element for selectively directing heated air from the conduit to the thermal responsive member and for utilizing the kinetic energy of the heated air discharged from said A m ni; outlet to aspirate air from the room it ough the enclosure inlet opening to said thermal responsive member dependant upon the deviation of the room temperature from said selected value.

4. In a conditioned air regulating system, the combination of a damper controlling the flow of conditioned air to an enclosure, 2. first temperature responsive element controlling the position of said. damp a chamberor' sa d el m n a first ondu co e tin sa d am e with said enclosure, a second conduit connecting said chamber with a. variably obstructed opening, a valve member adjacent said opening and moveable between a first position wherein said opening has a maximum obstruction and a second position wherein said opening has a minimum obstruction, a. third conduit connecting said second conduit with the conditioned air supply and adapted to discharge conditioned air through said second conduit. and out said opening as said valve member approaches its second position and to direct conditioned air through said second conduit to said first temperature responsive element as said valve member approaches its first position, a second temperature responsive element controlling the position of said valve member, whereby the position of said damper is controlled by the differential in temperature existing between the conditioned air temperature and the enclosure air temperature through the operation of the. air aflecting said first temperature responsive element, said last mentioned air comprising enclosure air aspirated through said first conduit when said valve member approaches its second position and comprising conditioned air directed through said second conduit when said valved member approaches its first position.

5. In an apparatus for controlling the flow of conditioned fluid from a source thereof into an enclosure the condition of which is to be maintained at a selected value: a first condition responsive member responsive to the condition of said enclosure, a second condition responsive member operable to vary the flow of conditioned fluid into said enclosure and means for changing the condition of the fluid ambient to said second condition responsive member, said means including a chamber having openings and housing said second condition responsive member, one of said openings connecting said chamber with said enclosure at a position opposite from the other of said openings, a conduit extending from said source of conditioned fluid to said chamber, and closure means for said other opening and operable by said first condition responsive member to selectively direct conditioned air to said second condition responsive member and to aspirate enclosure air through said inlet opening to said second condition responsive member.

6. In an apparatus for controlling the flow of conditioned fluid from a source thereof into an enclosure the conditlon of which is to be maintained at a selected value: a first condition responsive member responsive to the condition of said enclosure, a second condition responsive member operable to vary the flow of conditioned fluid into said enclosure, a conduit connecting said second condition responsive member with said enclosure, and means controlled by said first member utilizing the kinetic energy of the conditioned fluid for drawing fluid from said enclosure to said second member through said conduit and for directing conditioned fluid from the source to said second member, dependant upon the deviation of the enclosure condition from said selected value.

7. In an apparatus for controlling the flow of heated air from a source thereof into a room the temperature of which is to be maintained at a selected value: a first thermal responsive member responsive to the temperature of the room, a second thermal responsive member operable to vary the flow of heated air into the room, a

7. conduit connecting said second thermal responsive member with the room, and means controlled by said first member utilizing the kinetic energy of the heated air for drawing air from the room to said second member through said conduit and for directing heated air from the source to said second member dependant upon the deviation of the room temperature from said selected value.

8. In a conditioned air regulating system, the combination of a conditioned air conduit forming a source of conditioned air and leading to an enclosure, a damper controlling the admission of conditioned air to said enclosure, a first temperature responsive element controlling said damper in accordance with temperature changes affecting said element, a system of conduits connecting said conditioned air conduit with said first temperature responsive element, connecting said enclosure with said first temperature responsive element and connecting said con ditioned air conduit with a valved opening, a second temperature responsive element controlling said valved opening whereby enclosure temperature changes affecting said second temperature responsive element vary the size of said valved opening to change the direction of flow of air affecting said first temperature responsive element to selectively provide conditioned air and enclosure air and thereby change said damper position.

CLIFFORD HOTCHKISS.

JUSTIN A. DEUBEL.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date Re. 22,870 Peple Apr. 15, 1947 1,181,443 Fulton May 2, 1916 1,875,851 Carson Sept. 6, 1932 1,917,880 Frantz et al July 11, 1933 2,241,108 Ackers M May 6, 1941 2,440,052 Lingen et a1. Apr. 20, 1948 2,487,367 Peple Nov. 8, 1949 2,523,497 Copping Sept. 26, 1950 

